ANTIGEN-ANTIBODY REACTIONS 401 



]iat2;e 408 and tlie ('ai])()hy(lrate determinants dcscril)cd 

 on page 411 . 



Heidelberger and Kendall showed that partially 

 hydrolysed Type III polysaccharide, giving products with 

 molecular weights between 550 and 1,800, gave reactions 

 with horse antisera but not with those from the rabbit ; 

 the aldobionic acid itself gave no reaction with either 

 antiserum. This suggests that definite groups and not 

 the molecule as a whole are concerned. Type III poly- 

 saccharide which has been methylated by dimethyl 

 sulphate and sodium hydroxide (reagents which do not 

 esterify the carboxyl group) reacts with the horse anti- 

 serum, precipitating about two -thirds of the nitrogen of 

 the antibody. The remaining one-third of the nitrogen 

 can only be precipitated by unmethylated polysaccharide 

 in which the hydroxyl groups are free. This confirms that 

 different groupings of a hapten may act independently 

 in stimulating the production of antibodies and in reacting 

 with. them. That is, a single antigen may j^roduce more 

 than one antibody with specificities corresponding to 

 different determinant groups in the antigen. 



For further reading : — 



W. C. Boyd, " Fundamentals of Immnnology." Chapter VI, Interscience 

 Publishers, Inc. New York, 1943. 



K. Landsteiner, " The Specificity of Serological Reactions," Harvard 

 Univer&ity Press. Cambridge, Mass,, 1945. 



J. R, Marrack, " The Chemistry of Antigens and Antibodies." Medical 

 Research Council Special Report No. 230. H. M. Stationery Office, 

 London, 1938. 



W, T. J. Morgan, " A Conception of Immunological Specificity." J. Hygiene, 

 37 (1937), 372. 



L. Pauling, " Theory of the Structure and Process of Formation of Anti- 

 bodies." J. Amer. Chem. Soc. 62 (1940), 2643, 



L, Pauling, D, H. Campbell and D, Pressman, " The Nature of the Forces 

 between Antigen and Antibody and of the Precipitation Reaction," 

 Physiological Reviews, 23 (1943), 203, 



L. Pauling and co-workers, " The Serological Properties of Simple Sub- 

 stances," J. Amer. Chem. Soc, 64 (1942), 2994, 3003, 3010, 3015; 

 65 (1943), 728, 



H, G. Wells, " The Chemical Aspects of Immunity," American Chemical 

 Society Monograph Series. The Chemical Catalog Company. New 

 York/ 1929. 



